Color oscillograph recording paper containing a color developing agent



Dec. 30. 1969 M,DuM s 3,486,890

COLOR OSCILLOGRAPH RECORDING PAPER CONTAINING A COLOR DEVELOPING AGENT Filed-June 9, 1965 Ill/l 1/ INVENTOR DEWEY M. DUMER 5 ATTORNEYS United States Patent 3,486,890 COLOR OSCILLOGRAPH RECORDING PAPER CONTAINING A COLOR DE- VELOPING AGENT Dewey M. Dumers, Binghamton, N.Y., assignor to GAF Corporation, New York, N.Y., a corporation of Delaware Filed June 9, 1965, Ser. No. 462,501 Int. Cl. G03c 7/20 U.S. Cl. 96-22 Claims ABSTRACT OF THE DISCLOSURE Multicolor light-sensitive recording paper susceptible to rapid processing, having on a support, a green sensitive silver chlorobromide or bromoiodide emulsion of low blue sensitivity containing a magenta color former, a gelatin layer containing a color developerespecially p-phenylene diamine, an overlying blue sensitive silver bromoiodide emulsion containing a cyan color former, and a gelatin surface layer containing a color developer, said paper yielding traces of different colors when exposed respectively to yellow, magenta or white light.

This invention relates to a multicolor photosensitive recording paper which has utility for rapid access photographic recording, and which does not require the use of solutions which contain a color developing agent.

Owing to the fact that dynamic recording has increased in application and importance, there have evolved fields of use in which a very short access time is desirable. The term access time is used to indicate the time interval between the exposure of a photosensitive recording paper to a light stimulus to be recorded and the presentation of the resultant record for visual observation. The terms photographic paper and recording paper are used throughout the specification and claims to include photosensitive emulsions disposed on any suitable support such as paper, film or other usable medium. For example, wind tunnel and flight testing procedures where rapid access is of considerable value. Quick inspection of recorded data improves efiiciency in changing conditions of operation to obtain additional necessary data. Moreover, test results can be recorded and visually observed in a brief, rather than a prolonged, interval of time.

Heretofore, conventional photographic recording techniques, generally referred to as oscillography, have involved the exposure of an entire roll of a record paper to the information to be recorded with subsequent and separate chemical development of the roll thus exposed. In this procedure a record roll of approximately 250- 400 feet in length was entirely exposed before its removal from the oscillographic recorder and its subsequent development by conventional means. This prior procedure required a rather long access time of minutes or even hours.

Advantageously, a high speed developing process has been proposed which permits visual access of a photographic record in as short a time as one second after exposure. This is accomplished by moving a strip of photographic recording paper through a film magazine at high speed past a spot of light which moves in accordance with the signal to be measured. As soon as the paper moves past the light spot, the emulsion on the paper is wetted with a thin film of a high energy alkaline proc- 3,486,890 Patented Dec. 30, I969 ice essing solution, which is almost immediately dried as the paper passes over a hot platen. At very rapid paper travel speeds the dried developed record may emerge fully developed from the magazine within as little as one second after exposure.

\ This photographic technique produces a record with very short access time, but the recorded data on the photographic recording paper is represented as a trace having but one color, for example, a black trace against an essentially white background. The advantage, therefore, of a multicolor recording paper capable of recording oscillograph traces in at least three colors is readily apparent. Accordingly, the present invention provides an improved multicolor oscillograph recording paper designed for recording oscillograph traces in at least three colors. Thus the invention provides a novel material for use inoscillograph recording which will improve trace separation, as well as readout. In addition, the present invention provides a high speed color processing system having a short access time which closely approximates the'ease-of-handling associated with conventional black and white papers. Compared with other color processing techniques, the new procedure makes it possible to use a minimum number of processing solutions.

Broadly, the invention contemplates a photographic multicolor paper having a color developing agent coated as an integral part thereof. In more detail, this photographic paper comprising a flexible support bearing on at least one surface thereof, (a) an undercoating comprising a green sensitive silver halide emulsion of low blue sensitivity being practically insensitive above 460 m before optical sensitization and containing a magenta color former, (b) a gelatin layer containing a color developing agent, (0) another coating comprising a high blue sensitive silver bromoiodide emulsion which may contain an optical sensitizing dye for the blue and containing a cyan color former and (d) a gelatin surface layer containing a color developing agent. The lower silver halide emulsion layer contains as the light-sensitive material either silver chlorobromide, silver bromide or silver bromoiodide with an iodide content of from 0.5 to 2.0 mole percent. The upper blue sensitive layer contains a silver bromoiodide emulsion in which the iodide content ranges from 6 to 10 mole percent.

Briefly, the invention contemplates exposing the photosensitive emulsions to light in an oscillograph recorder which is provided with suitable colored filters in front of its galvanometers. After exposure to light, the exposed emulsions are developed by wetting them with an aqueous alkaline processing solution, for example, with a 1 to 3 percent sodium hydroxide solution which may contain from 1 to 10 grams of potassium or sodium bromide per liter.

The term processing solution is used throughout the specification and claims to designate primarily a development activation solution which contains an alkali metal hydroxide as its active ingredient to create a pH of at least 13. The solution may also include additives such an antifoggants or restrainers, e.g., an alkali metal bromide or iodide, benzotriazole, nitrobenzimidazole, mercaptobenzimidazole, l-phenyl-S mercaptotetrazole and the like; hardening agents such as formaldehyde, glyoxal, triacrylformal, glutaraldehyde bisulfite and the like.

The developing procedure generally outlined above can be carried out nearly simultaneously with the exposure of the recording medium to the light to be recorded. The processing solution may be applied as a thin film immediately after this exposure, but it is necessary that the exposure precede the application of the alkaline solution.

One form of apparatus for performing the steps of the invention is shown in the schematic elevation in the accompanying drawing.

Referring to the drawing a record handling unit is enclosed in a magazine 12 having on one side a window 14 through which a light beam 16 produced in a conventional recording camera enters the magazine. The camera is illustrated schematically as a light source 18 and a modulator 20 represented as a galvanometer mirror with a color filter 22 being positioned thereon. The camera, as such, forms no part of the present invention and is conventional in the process of oscillography. In the usual commercially employed oscillograph, a number of channels of data may be recorded at the same time by using a plurality of light modulators with filters and recording the modulations responsive to separate signals applied to the respective modulators and representing a plurality of parameters to be recorded.

Typically, a plurality of pressure transducers may be incorporated in various locations of a wind tunnel with their outputs separately connected to a different one of a plurality of galvanometers in a multi-channel oscillograph. For purposes of describing the invention a single galvanometer mirror 20 plus filter 22 is shown as illustrative of the phenomena involved with the invention and is representative of any number of separate channels of recording.

The magazine 12 houses a supply roll 24 on which an unexposed strip of recording medium 26, e.g., a multicolor photographic recording is stored. The record is carried over a metering roller 28 driven by conventional roller drive means (not shown) to determine the speed of travel of the recording medium through the magazine. The metering roller is adjacent the magazine opening so the light beam strikes the photographic emulsions (not shown) on the paper as it passes over the metering roll. From the metering roller the record is carried around an idling or tension roller 30 and from there past a processing solution applicator 32.

The applicator 32, as shown schematically in the drawing, comprises a processing solution reservoir 34, a socalled slit applicator 36 which communicates at one end with the reservoir 34 and is open through a narrow slit (not shown) at another end, which bears against the recording paper 26 as it is stretched across a mandrel 38.

The latent image produced in the recording medium at the instant of exposure through window 14 would not be rapidly developed after application of the processing solution at the applicator 36 without further impetus. However, at this point, the record cannot be exposed to ambient light since the emulsion is still highly sensitive to light while it is damp. Accordingly, the crux of rapid access is the application of large quantities of heat relative to the amount of developer present to induce rapid development and simultaneous drying of the thin film of developer. This is facilitated when a small volume of developer is used and the recording paper itself has not been wet.

To achieve fast heating of the wetted emulsion, the paper is carried from the applicator 32 over a guide roller 40 and across a curved face 42 of a heated platen 44.

The dimensions of the platen are selected to achieve the desired degree of drying at the ranges of paper speed to be encountered and under acceptable conditions of temperature. Generally speaking, we have found that the record can be dried at a temperature in excess of about 90 C. and preferably in the neighborhood of 120 C. requiring a drying time of approximately 0.4 second. The platen 44 may be heated in conventional fashion by insert heaters (not shown). To accomplish the rapid drying desired, it is necessary to transfer relatively large quantities of heat to the record. This can be accomplished by high power input to the platen but preferably is done by causing the platen to act as a heat sink storing relatively large amounts of heat developed at comparatively low power consumption during periods of inactivity, e.g., while the record roll is being changed. Any form of heated platen may be employed, there being many adequate to apply the necessary heat to the record.

From the platen the record is passed through compression rolls 46, 48, the roller 48 being driven through a slip clutch to maintain a constant tension on the record strip between the metering roll 28 and the point of the compression rollers. Thereupon the record is discharged from the magazine through an exit slit 50.

When using the color oscillograph paper of this invention, the record obtained from the magazine permits a faster readout, with less chance for error, when utilized with multichannel recordings. Furthermore, the record obtained is sufficiently stable to permit leisurely visual observation without significant subsequent staining or darkening.

The purpose of incorporating the color developing agent as an integral part of the coating is to minimize the time required for diffusion of the color developing agent to the areas of silver halide exposure. This is especially important in the case of the undercoating layer. By incorporating a color developing substance in the coating, it is only necessary to supply alkali to accomplish development of the exposed halide and subsequent imagewise dye formation.

The photographic silver halide emulsions which can be advantageously employed in the recording papers of this invention are the type customarily employed in the art and include the well-known types of silver chlorobromide and silver bromoiodide emulsions. It is preferred that the outer silver bromoiodide emulsion coating have a higher blue speed than the lower silver chlorobromide emulsion, when measured at 460 millimicrons. The speed of the upper bromoiodide emulsions with the high iodide content exceeds the speed of the lower silver chlorobromide emulsion or of the silver bromoiodide emulsion with the low iodide concentration by a factor of at least 8, corresponding to at least 3 stops.

In accordance with the invention, the color formers employed herein are those which are commercially available and are well-known in the art. The term color former, as used throughout the specification and claims, defines a chemical substance which is capable of reacting with the oxidation product of an aromatic p-amino developing agent, preferably of the p-phenylenediamine series, e.g., 4-N,N-diethyl-4-amino aniline, 4-(N,N-di-B- hydroxyethyl) aminoaniline to form dyes of the quinoneimine, indoaniline, azomethine or phenazine (azine) series. These color formers which are fast to diffusion are well-known in the art and are described inter alia in U.S. Patents 2,500,487; 2,547,307; 2,829,975 and others. Among the conventional color formers are the following compounds: l-octadecyl 2 (2,1' hydroxynaphthyl)-benzimidazole-S-sulfonic acid as a cyan color former; l-(4'-phenoxy 3' sulfophenyl) 3 stearyl-S- pyrazole as a magenta color former and 2-(4-benzolylacetaminophenyl)l-octadecylbenzimidazole 5 sulfonic acid as a yellow color former. Generally speaking, the quantity of color former used per unit of silver halide is selected in such a way that sufiicient density of the trace is achieved upon exposure and developing so as to provide proper readout. Specifically, it is recommended that the ratio of color formers to silver halide per silver halide emulsion layer be about 10 millimols of color former to about 2 to 20 grams of silver halide.

The invention contemplates the use of sensitizing dyes capable of sensitizing in the green and, if desired, in the blue region of the spectrum. It is preferred that the dye or dyes should be non-migratory or fast to diffusion in the emulsion in which it is present so that the dye cannot wander freely from one layer to another layer. Nonlimiting examples are cyanine, carbocyanine, merocyanine, styryl and related sensitizing dyes.

In addition to the foregoing ingredients, other emulsion additives, such as wetting agents, antifoggants, or stabilizers may be employed.

The invention will be further illustrated by, but is not limited to, the following examples.

EXAMPLE I A multicolor recording paper was prepared by adding to 1000 grams of chlorobromide emulsion of low blue sensitivity the following ingredients: 120 cc. of a 1:2000 solution of a sensitizing dye for the green; 0.5.gram of an antifoggant; 30 cc. of a solution of the ammonium salt of a sulfate ester of an alkyl phenoxypolyoxyethylene ethanol which serves as a wetting agent and coating aid; and grams of a magenta color former having the formula: v

Sufiicient water was added to the above emulsion so as to adjust it to the proper viscosity for coatingjon a 55 gram Document paper (100% rag). This coating was applied in a thickness corresponding to a coating weight of 0.4 to 0.5 of metallic silver per square meter.

In the same operation, but at a different station, the following gelating surface layer was applied to' a thickness of 1.0g. This layer was, prepared from 35 grams of gelatin, 1 liter of water; 15 grams of 4-N,N-di( 8- hydroxyethyl)-aminoaniline which serves as a. color developing agent; cc. of the above described wetting agent; 0.25 gram of sodiurn',,bisulfite and a sufficient amount of a 10% solution of sodium carbonate to adjust the mixture to a pH of 7.0.

In a second coating operation, to 1000 grams of a high speed bromoiodide emulsion was added 0.5 gram of an antifoggant, a 10% solution of the ammonium salt of a sulfate ester of an alkyl phenoxypolyoxyethylene ethanol which serves as a coating aid; and 15 grams of a cyan color former having the formula:

1 (FxsHar COOH COOH

Absorption Filter Color Galilanometer identification:

Upon exposure and subsequent travel past the developer applicator which contained 20 grams of sodium hydroxide and 5 grams of potassium bromide per liter, the following results were obtained:

EXAMPLE II Example I was repeated with the exception that the silver chlorobromide emulsion of the lowest layer was replaced by a silver bromoiodide emulsion with an iodide content of 1.5 mole percent. The results obtained were essentially identical with those obtained with the rec rding material of Example I.

Modification of the invention will occur to persons skilled in the art. It is, therefore, not intended to be limited in the patent granted except as necessitated by the appended claims.

I claim:

1. A multicolor light-sensitive recording paper for rapid access photographic color recording which comprises a flexible support bearing on at least one surface thereof, (a) an undercoating' comprising a green sensitive silver halide emulsion in which the silver halide is selected from the group consisting of silver chlorobromide and silver bromoiodide with from 0.1 to 2.0 mole percent of iodide, and containing a magenta color former, (b) a gelatin separation layer containing a color developing agent, (0) a blue sensitive silver bromoiodide emulsion layer containing a cyan color former, and (d) a gelatin surface layer containing a color developing agent.

2. The article of elaim 1 in which the blue speed of the upper silver bromoiodide emulsion layer exceeds the blue speed of the lower silver halide emulsion layer by a factor of about 8 when measured at 460 m 3. The article ofclaim 1 in which the magenta color former has the formula:

4. The article of claim 1 in which the cyan color former has the formula:

COOH

5. A process of forming a multicolored image which comprises exposing with a plurality of selectively filtered colored lights, a multicolor light-sensitive recording paper for rapid access photographic color recording which comprises a flexible support bearing on at least one surface thereof, (a) an undercoating comprising a green sensitive silver halide emulsion in which the silver halide is selected from the group consisting of silver chlorobromide or silver bromoiodide with from 0.1 to 2.0 mole percent of References Cited iodide and containing a magenta color former, (b) a UNITED STATES PATENTS gelatin separation layer containing a color developing agent, (0) a blue sensitive silver bromoiodide emulsion 3,212,895 10/1965 Barbler et a1 9695 layer containing a cyan color former, and (d) a gelatin 3,265,503 8/1966 Bodmer et surface layer containin a color developin agent, and treating the selectively Exposed multicolor riaterial with NORMAN TORCHIN Pnmary Examiner an aqueous solution containing an alkali mefal hydroxide MARY F. KELLEY, Assistant Examiner so as to provide the necessary alkaline medium to permit the coupling of the color former and the oxidation prod- 10 US. Cl. X.R.

nets of the color developing agent in the exposed areas. 96 74 77 Disclaimers 3,486,890.Dewey M Dumers, Binghamton, N.Y. COLOR OSCILLOGRAPH RECORDING PAPER CONTAINING A COLOR DEVELOPING AGENT. Patent dated Dec. 30, 1969. Disclaimer filed Sept. 30, 1982, by the assignee, Eastman Kodak Co. Hereby enters this disclaimer to all claims of said patent. [Oflicial Gazette March 22, 1983.] 

